Drill collar



'March 8, 19322.v F. J. -uNDRLlTl-:R

DRILL COLLAR Filed Dec. 26 1929 warum A TTORNE y 'y Patented l Mar. 8,1932 UNITED STATES "PATENT OFFICE y 'FRANK J'. HINDERLITEB, 0F TULSA.,OKLAHOMA, ASSIGNOB TO HINDERLITE TOOL (30H1` PANY, F TULSA, OKLAHOMA, A,CORPORATION 0F OKLAHOMA mum. oLLAn Application led December 26, 1929.Serial 11e-416,467.

M y'invention relates to rotary well drilling apparatus, and moreparticularly to the'drill -.collar which isinterposed between the drillpipe and bit of a tool string.

In drilling wells with rotary. tools, the working tool or bit is carriedat the lower end of a drill pipe and cuttings removed by the bit areflushed from the well with mud-laden fluid circulated through the toolstring andI well.- .As greatest torsional strain on the string occursjust above the bit, collars of greater strength and consequently ofgreater diameter than the drill pipe are interposed at this point forabsorbing the exceptionaltorsional or twisting strain incident tothe'drilling operation. y

The mud-laden fluid passed through the pipe and collar is ordinarilydelivered from the bit with sufficient force to scour the bit and liftits cuttings through the well hole about the collar and pipe, but shouldflow of the fluid be interrupted, mud precipitating from the fluid willsettle on the annular shoulder at the top of the collar and form anobstruction known as a mud ring of sufficient volume and density tointerfere-with removal of thel tools.

It is the object of my invention to provide a. drill collar wherebyformation of such obstruction may be avoided withoutsacrifice of freedomof circulation of fluid or impairment of strength of the bit coupling,and whereby any formation occurring above'the -collar during thedrilling operatlon may be removed to permit'withdrawal of the tools.

In accomplishing this object, I have pro'- vided improved details ofstructure, the vpreferred form of which is illustrated 1n theaccompanying drawings,wherein:

Fig.'A 1 is a perspective view of the lower end of a tool stringincluding a drill collar constructed according to my invention,illustrating operation of the tool in a well hole, shown in verticalsection.

Fig. 2 is'an enlarged detail perspective vie of the collar, partlybroken away for better illustration. f

Fi ..3 is a similar viewof a slightly modified ormof collar. l

Referring in detail to the drawings:

ed externally and internally, respectively, for

attachment to the ste-m' coupling' 4 and bit shank 5,' 'and an enlargedbody portion 10 having longitudinal grooves llrectangular in-crosssection, formed between spaced ribs 12 extending from end to end of thebody,

and forming Waterl courses for free flow of the circulating fluidtherethrough, the upper end of the body portion l10 being reduced tofacilitate lift of the collar through the well,

and theupper ends ofthe ribs 12 being tapered toward their forward edgesto form cutting tips .13 for cutting a path Vthrough any deposit of mudthat may have accumulated in the well above the collar when the toolsare being removed from the well hole. The side edges of the' ribs arepreferably sharp to effect a reaming action on the wall of the well, andthe lower ends of the ribs are also preferably tapered toward theirforward edges and extended beyond the lower end of the body to formcutting tips 14 for cutting irregular projections'from the wall ofthewell while the drilling is in progress.

In 'the preferred form of structuren the grooves forming the watercourses extend in straight lines through the body of the collar, butthey may be curved, as shown at 15 in Fig. 3, if desired, to impart anauger action when the tools are in operation.

A tool string equipped with a collar con'- structed according to myinvention, may be operated in the usual manner except that circulatingfluid delivered from the bit and mixed with cuttings instead of passingup- '-1 wardly around the collar is ejected through the Water courses 1nthe collar with sufficient force to prevent' formation of a mud ringover the collar while the drilling is n progress. The cuttin'g tips atthe lower ends of theribs remove irregular projections left by the biton the wa'll of the hole which might tend to deliect the collar, and thelarge body of the collar holds the tools straight and insures a straighthole. Should a ring form or c'avings accumulate over the collar to anextent which would ordinarily' obstruct removal of the tools, fluidcirculated through the water courses during removal of thetools will beejected from the water courses with sufficient force to cut a way forthe collar and avoid the sticking which would otherwise occur.

While 'clearance of the well hole above the collar is the principaladvantage desired from y use of a collar of my improved construction,

the other advantages heretofore noted as incident to this principalfeature of improvel ment add their measure of utility to the tool.

What I claim and desire to secure by Letters Patent is:

' 1. A drill collar including a body portion having spaced integral ribsrectangular :in` cross section on its outer face formingV groovesrectangular in cross section for forming wa- -ter courses, and havingcutting'edges llongitudinally of said ribs for reaming the wall of -lhawell hole within which the collar is` employed, said ribs having taperedends forming transverse cutting edges on said ribs.

2. A drill collar including a body portion having spaced longitudinalribs on its outer face forming water courses therebetween,

Vedges of said grooves,

said ribs having forwardly tapering tips at their upper and lower endsprovided with transverse cutting edges,v the length of said cuttingedges being equal to the depth of the water courses, and an upper shankof less diameter than the body portion including a. tapered shoulderjoining said shank and the collar.

3. A drill collar comprising a body portion having a tapered and a bluntend and having longitudinally extending parallel grooves in lits outerface so as to form cutting edges along one longitudinal edge and bothadjacent end an internally screw threadedshank of less diameter than andintegral with the blunt end of said body portion, a reduced shankintegral with the taf pered portion of said body portion, and a couplingmember carried by the free end of said last mentioned shank.

4. A drill collar comprising a cylindrical body portion having a centralbore therethrough and a flat end and a tapered end, longitudinallyextending' parallel, spaced apart, radially projecting ribs formedintegral with the body portion and forming'water courses therebetween,cutting edges formed on one of the longitudinal edges and both ends ofsaid ribs, a centrally located internally screw threaded shank of lessdiame-

